\subsection{{\tt{convex}}: Convex Hull\label{s:toys-convex}}

Given a set of $(x,y)$ points,
this toy finds those that lie on the convex hull,
removes them,
then finds the convex hull of the remainder.
This process continues until no points are left.
The output is a list of points in the order in which they were removed,
i.e.,
the first section of the list is the points from the outermost convex hull,
the second section is the points that lay on the next hull, and so on.

{\inputspec}

\begin{description}
\item[{\tt{original}}:]
	the vector of input points.
\end{description}

{\outputspec}

\begin{description}
\item[{\tt{ordered}}:]
	the vector of output points (a permutation of the input).
\end{description}
